鄱阳湖地区大气边界层特征的数值模拟

Numerical simulation of features of boundary-layer over Poyang Lake area

采用WRFV2.2中尺度数值模式对鄱阳湖地区200 km×200 km范围内,2009年11月5日00:00至2009年11月6日12:00不同高度的气象要素进行了数值模拟,得到了水平分辨率为1km的鄱阳湖地区大气边界层风、温、湿度场和廓线分布的大气边界层物理特征.模拟结果发现:(1)白天鄱阳湖面上空存在着冷岛效应并伴随湖风,而夜间湖面上空存在着热岛效应并伴随陆风,湖面与陆地之间最大温差可达6℃;(2)地形以及下垫面类型对鄱阳湖区风场的分布具有很大影响,夜间存在一条东北西南走向的低空辐合带,白天逐渐消失;(3)受风场和地形作用湖面上空的湿度分布也不均匀,白天湿度层厚度低而夜晚湿度层厚度高,湖中心右侧湿度值大于左侧湿度值.模拟结果能较好地反映鄱阳湖的大气边界层物理特征,有助于了解鄱阳湖地区区域气候的特点,以及由于地形、地理环境、地表特征所形成的不同高度上的风、温、湿的分布规律和大气边界层物理特征,为鄱阳湖地区局地天气预报、风能资源开发、环境保护等提供了科学依据.

In this paper WRFV2.2 mesoscale numerical model is used to simulate meteorological elements of different heights over Poyang Lake area within 200 km × 200 km range. We got the wind, temperature, humidity fields and the profile distribution of Poyang Lake area atmospheric boundary layer with the high-resolution of 1 km, from 00 ： 00 Nov 5, 2009 to 12：O0 Nov 6, 2009. The results show that： （1） The cool island effect exists between the lake-land during daytime accompanied by lake wind, and the heat island effect at night accompanied by land breeze, the maximum temperature difference between lake and land is up to 6℃. （2） Meanwhile, the terrain and surface types on the Poyang Lake area has a great influence on the distribution of the wind, mainly there exists a southwest-to-northeast low-level convergence zone at night, which disappears during the day. （3） In addition , the role of wind and topography makes the lake＇s moisture distribution non uniform. The humidity thickness becomes lower during the day while on the contrary at night. On the right of Poyang Lake the humidity value is greater than the left. The results relatively well reflect the distribution of meteorological elements within the boundary layer in Poyang Lake area, which can help us to understand the characteristics of regional climate, and the distribution of wind, temperature and humidity at different levels. It provides a scientific basis for the Poyang Lake area local weather forecast, wind energy resource development and environmental protection.